WASHINGTON -- The Washington Capitals entered the third period Wednesday night trailing the Buffalo Sabres 2-1 and playing without their top-line center.

Evgeny Kuznetsov stepped in, made a pair of pretty passes, and the Capitals rallied past the Buffalo Sabres 5-2 for their ninth straight win.

Alex Ovechkin scored two third-period goals, including an empty-netter, and Marcus Johansson scored the go-ahead goal and added an assist. Kuznetsov, stepping in for Nicklas Backstrom who left with an upper-body injury in the second period, set up the tying and go-ahead goals, giving him 22 assists.

"He knows where everybody is. He puts it right on your tape. I probably could score a couple of goals playing with him," Capitals head coach Barry Trotz joked afterwards.

Trailing 2-1, Washington scored four third-period goals to improve to 16-1-1 over their last 18 games.

Ovechkin tied the game at 1:24 of the third period when Kuznetsov took a pass as he was skating behind the net and fed it behind him right in front to Ovechkin, who back-handed a shot past Sabres goalie Chad Johnson (38 saves).

Then on a power play, Kuznetsov skated toward the net from the right circle and fed in front to Johansson, whose redirect gave Washington its first lead of the night.

"He's finding new ways to create space for himself," goalie Braden Holtby (25 saves) said of Kuznetsov. "His puck control is just phenomenal and that's why he can create those opportunities."

Left winger Andre Burakovsky gave Washington a two-goal cushion a little over a minute later, and Ovechkin notched his 20th of the season into an empty net with 1:13 left.

Right winger Justin Williams also scored for Washington.

"We exchange power plays in the third period there and we have an opportunity to go up in the game with a power play, and then when (Washington) gets theirs they go up with it," Sabres head coach Dan Byslma said. "That was the difference in the game really."

The Capitals (28-6-2) poured 43 shots on net as they continued their best start in franchise history and moved ahead of idle Dallas for the NHL points lead.

The news wasn't all good, however. While Trotz said Backstrom could return as early as Thursday, center Jay Beagle left the game as well. Trotz said he'll have upper-body surgery and will miss extended time.

Center Zemgus Girgensons had a goal and an assist for Buffalo, and right winger Brian Gionta gave the Sabres a 1-0 lead in the first. Rookie center Jack Eichel had two assists.

"We gave it to them," Girgensons said. "We made way too many mistakes in the whole game (and) that's one team that you can't give that many opportunities to score. They've got guys who can put the puck in."

The Sabres got the only first-period goal off a pretty passing sequence at 5:38.

Girgensons dropped a pass back to Eichel in the slot. Eichel stick-handled between two Capitals and backhanded a pass across to Gionta, whose redirection trickled past Holtby.

Johnson's first mistake of the night was costly when he went behind his own net to play the puck. Seeing Kuznetsov closing in, he quickly sent the puck to the other side, right to the waiting Williams, who tucked it home for his 11th goal of the season.

Despite being outshot 28-19, the Sabres took a 2-1 lead late into the second intermission.

When the rebound of an Eichel shot bounced high in the air in front of Holtby, Girgensons positioned himself and, when the puck landed, banged it home with 67 seconds left.

NOTES: Buffalo C Tyler Ennis left the game with an upper body injury and didn't return. … The Capitals last won nine straight from Feb. 26 to March 15, 2011. ... Washington C Michael Latta, who injured an arm during a fight with Buffalo LW Nicolas Deslauriers on Monday, was out of the lineup. D Brooks Orpik (lower body) missed his 22nd game and D John Carlson (lower body) his second. RW Stanislav Galiev was scratched. ... The Sabres began play 0 of 17 with the man advantage through six games. ... Buffalo scratched LW Matt Moulson and D Carlo Colaiacovo. ... Centers Jack Eichel (11 goals) and Sam Reinhart (eight) could become the second pair of Buffalo rookies to score 20 goals in the same season. Danny Gare (31) and Peter McNab (22) did it in 1974-75.